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Optimization of the Number and Location of Boreholes for Gassy Soil Site Investigation Considering the Statistical Uncertainty

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World Journal of Engineering and Technology 2024年第4期12卷 895-913页

作者： Shaolin Ding Quanhong Li Key Laboratory of Geotechnical Mechanics and Engineering of the Ministry of Water Resources Yangtze River Scientific Research Institute Wuhan China Mid-Route source of South-to-North Water Transfer Corp. Ltd. Danjiangkou China

The research addresses the prevalence of gassy soil, containing methane (CH4), within the soil particles of southeast coastal areas of China, such as the Quaternary deposit in the Hangzhou Bay area. This soil exhibits spatial variability in the distribution of gas pressure, posing a potential threat of engineering disasters, including fire outbreaks and blasting, during the construction of underground projects. Consequently, it is crucial to assess the risk state of gas pressure, involving accurate identification and reduction of associated uncertainty, through site investigation. This is indispensable prior to the commencement of underground projects. However, during the site investigation stage, the random field parameters that quantify the spatial variability distribution of gas pressure (e.g., mean value, standard deviations, and scale of fluctuation) are unknown, introducing corresponding statistical uncertainty. Therefore, the most significant consideration for planning site investigation from an engineering perspective involves determining the risk state of gas pressure while considering the statistical uncertainty of these random field parameters. This consideration heavily relies on the engineering experience gained from current site investigation practices. To address this challenge, the study introduces a probabilistic site investigation optimization method designed for planning the site investigation scheme for gassy soils, including determining the number and locations of boreholes. The method is based on the expected state-identification probability, representing the probability of identifying the risk state of gas pressure, and takes into account the statistical uncertainty of random field parameters. The proposed method aims to determine an optimal investigation scheme before conducting the site investigation, leveraging prior knowledge. This optimal scheme is identified using Subset Simulation Optimization (SSO) in the space of candidate site invest

关键词： Gassy Soils Site Investigation Subset Simulation Optimization (SSO) Uncertainty

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Experiment study on micro-structure on different crystallographic planes of mc-Si etched in alkaline solution

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Science China(Technological Sciences) 2012年第6期55卷 1509-1514页

作者： WANG KunXia FENG ShiMeng XU HuaTian TIAN JiaTong YANG ShuQuan HUANG JianHua PEI Jun Department of Physics Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Academy of Spaceflight Technology Shanghai 200235China Solarfun Power Holdings Solarfun Solar Shanghai Jiao Tong University R&D Center Shanghai 201109China Shanghai Shenzhou New Energy source Development Co.ltd Shanghai 20112China

The investigation of multi-crystalline silicon （mc-Si） surface etching technology is a key point in solar cell research. In this paper, mc-Si surface was etched in the common alkaline solution modified by an additive for 20 minutes at 78-80~C. Samples＇ surface morphology was observed by scanning electron microscope （SEM）. It is firstly found that the etched mc-Si surface has the uniform distribution of trap pits although the morphologies of trap pits are slightly different on different crystallographic planes. Si （100） plane was covered with many small Si-mountaln ranges or long V-shape channels arranged in a crisscross pat- tern. For （110） plane and （111） plane, they were full of a lot of triangle pit-traps （or quadrilateral holes） and twisted earthworm trap pits, respectively. The measured reflectance of the sample was 20.5% at wavelength range of 400--900 nm. These results illustrate that alkaline solution modified by an additive can effectively etch out trap pits with a good trapping light effect on mc-Si surfaces. This method should be very valuable for mc-Si solar cells.

关键词： mc-Si wafers chemical etching surface structure trapping effect reflectance

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Reaction mechanism of lanthanum nitrate-doped Mo–La material during solid–liquid spray doping processing

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Rare Metals 2015年第11期34卷 814-817页

作者： Peng-Fa Feng Qin-Li Yang Xiao-Ming Dang Sha Xi Ya-Qi Wang Jinduicheng Molybdenum Co. Ltd

At three critical temperatures which were obtained by thermo-gravimetry-differential thermal analysis–differential scanning calorimetry（TG/DTG/DSC）curves of lanthanum nitrate crystal, the air thermal decomposition experiments and solid–liquid spray doping simulation procedures of lanthanum nitrate crystal were carried out, and their products were analyzed by X-ray diffraction（XRD）. Meanwhile, the spray doping processing of Mo O2–50 wt% La（NO3）3composite powder was undergone with lanthanum nitrate solution as the dopant,and doped Mo O2powder was analyzed by XRD. The results demonstrate that during the traditional solid–liquid spray doping processing, lanthanum nitrate, in the form of either crystal or aqueous solution, would be converted into La（NO3）3á4H2O by the dehydration reaction, rather than be decomposed to La2O3and NO or NO2. Therefore, it is inferred that the oxynitride gas produced from the process is attributed to the decomposition of residual HNO3in lanthanum nitrate crystal. The source of HNO3is supported by the chemical composition of lanthanum nitrate crystal.

关键词： Solid–liquid spray doping processing Mo O2 Lanthan

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Changes in factor profiles deriving from photochemical losses of volatile organic compounds:Insight from daytime and nighttime positive matrix factorization ana

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Journal of Environmental Sciences 2025年第5期151卷 627-639页

作者： Baoshuang Liu Tao Yang Sicong Kang Fuquan Wang Haixu Zhang Man Xu Wei Wang Jinrui Bai Shaojie Song Qili Dai Yinchang Feng Philip K.Hopke State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control&Tianjin Key Laboratory of Urban Transport Emission Research College of Environmental Science and EngineeringNankai UniversityTianjin 300350China CMA-NKU Cooperative Laboratory for Atmospheric Environment-Health Research Tianjin 300350China Beijing Make Environment Science&Technology Co. Ltd.Beijing 100083China Shijiazhuang Environmental Prediction Center Shijiazhuang 050022China Department of Public Health Sciences University of Rochester School of Medicine and DentistryRochesterNY 14642USA Institute for a Sustainable Environment Clarkson UniversityPotsdamNY 13699USA

Substantial effects of photochemical reaction losses of volatile organic compounds(VOCs)on factor profiles can be investigated by comparing the differences between daytime and nighttime dispersion-normalized VOC data resolved *** speciated VOC data measured in Shijiazhuang,China from May to September 2021 were used to conduct *** mean VOC concentration in the daytime and at nighttime were 32.8 and 36.0 ppbv,*** and aromatics concentrations in the daytime(12.9 and 3.08 ppbv)were lower than nighttime(15.5 and 3.63 ppbv),whereas that of alkenes showed the opposite *** concentration differences between daytime and nighttime for alkynes and halogenated hydrocarbonswere uniformly *** reactivities of the dominant species in factor profiles for gasoline emissions,natural gas and diesel vehicles,and liquefied petroleum gas were relatively low and their profiles were less affected by photochemical *** losses produced a substantial impact on the profiles of solvent use,petrochemical industry emissions,combustion sources,and biogenic emissions where the dominant species in these factor profiles had high *** the profile of biogenic emissions was substantially affected by photochemical loss of isoprene,the low emissions at nighttime also had an important impact on its *** losses of highly active VOC species substantially reduced their concentrations in apportioned factor *** study results were consistent with the analytical results obtained through initial concentration estimation,suggesting that the initial concentration estimation could be the most effective currently availablemethod for the source analyses of active VOCs although with uncertainty.

关键词： Volatile organic compounds Dispersion normalization Photochemical loss Factor profile Positive matrix factorization

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Exciton-harvesting enabled efficient charged particle detection in zero-dimensional halides

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light(Science & Applications) 2024年第9期13卷 1944-1955页

作者： Qian Wang Chenger Wang Hongliang Shi Jie Chen Junye Yang Alena Beitlerova Romana Kucerkova Zhengyang Zhou Yunyun Li Martin Nikl Xilei Sun Xiaoping OuYang Yuntao Wu Shanghai Institute of Ceramics Chinese Academy of SciencesShanghai 201899China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China National Engineering Research Center for Rare Earth Grirem Advanced Materials Co.Ltd.and General Research Institute for Nonferrous MetalsBeijing 100088China Department of Physics Beihang UniversityBeijing 100191China Spallation Neutron source Science Center Dongguan 523803China Department of Optical Materials Institute of Physics of the Czech Academy of SciencesPrague 16200Czech Republic Northwest Institute of Nuclear Technology Xi’an 710024China

Materials for radiation detection are critically important and urgently demanded in diverse fields,starting from fundamental scientific research to medical diagnostics,homeland security,and environmental *** halides(LDHs)exhibiting efficient self-trapped exciton(STE)emission with high photoluminescence quantum yield(PLQY)have recently shown a great potential as ***,an overlooked issue of excitonexciton interaction in LDHs under ionizing radiation hinders the broadening of its radiation detection ***,we demonstrate an exceptional enhancement of exciton-harvesting efficiency in zero-dimensional(0D)Cs_(3)Cu_(2)I_(5):Tl halide single crystals by forming strongly localized Tl-bound *** of the suppression of nonradiative exciton-exciton interaction,an excellentα/βpulse-shape-discrimination(PSD)figure-of-merit(FoM)factor of 2.64,a superior rejection ratio of 10^(−9),and a high scintillation yield of 26000 photons MeV−1 under 5.49 MeVα-ray are achieved in Cs_(3)Cu_(2)I_(5):Tl single crystals,outperforming the commercial ZnS:Ag/PVT composites for charged particle detection ***,a radiation detector prototype based on Cs_(3)Cu_(2)I_(5):Tl single crystal demonstrates the capability of identifying radioactive 220Rn gas for environmental radiation monitoring *** believe that the exciton-harvesting strategy proposed here can greatly boost the applications of LDHs materials.

关键词： composites particle dimensional

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Development of New Online Monitoring System of Adsorption and Concentration for Atmospheric Volatile Organic Compounds

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Journal of Chinese Mass Spectrometry Society 2019年第2期40卷 177-188页

作者： Wang, Fu-Hua Wu, Man-Man Qiao, Jia Chen, Jia-Xin Lv, Jin-Nuo Cai, Wei-Guang Wang, Jian-Kai Gao, Wei Institute of Mass Spectrometer and Atmospheric Environment Ji'nan University Guangzhou510632 China Guangzhou Hexin Instrument Co. Ltd Guangzhou510530 China Guangdong Provincial Engineering Research Center for On-line source Apportionment System of Air Pollution Guangzhou510632 China

In order to meet the requirement of monitoring VOCs for qualitative, quantitative analysis at low level, a new online monitoring system of adsorption and concentration was developed and preliminarily tested, which included a sampling gas path system with a dual channel, a ultra-low temperature trap system, a power supply, a control system, and an analysis system with gas chromatography-mass spectrometry/flame ionization detector (GC-MS/FID). A unique technology of two-stage cryogenic enrichment was adopted for the ultra-low temperature trap system, which included two trap tubes of first stage and two focusing tubes of second stage. Each tube was able to reach an ultra-low temperature of -160℃ and covered with a heating structure. A sampling gas path system with a dual channel was used as a processing device of front injection for analyzing application of MS and FID, before which sample was separated by GC. Each channel included a trap tube and a focusing tube. VOCs and water were cryogenically trapped in the tube of first stage during sampling and focused in the tube of second stage after the tube of first stage had been heated, but the water was still remained in the tube of first stage because the temperature was less than 100℃. All VOCs in the tube of second stage were heated to 170℃ and analyzed in the GC-MS/FID by carrier gas, when the twelve-way valve was switched. The valve was switched to the original position in two minutes later, and the gas path was completely purged for 10 min in the opposite direction of the trapping state, when all the tubes were heated to 180℃, then the system was going to be in the state of waiting for the sample to be trapped. This technology could adsorb and concentrate 100 kinds of VOCs including C2-C12 hydrocarbons, oxygenated organic compounds, halogenated hydrocarbons, organic sulfides and so on, as well as conducting online real-time monitoring and analysis. It was easy to get data about the information of VOCs concentration i

关键词： Cryogenics

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NOx storage and reduction assisted by non-thermal plasma over Co/Pt/Ba/γ-Al2O3 catalyst using CH_(4) as reductant

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Plasma Science and Technology 2021年第2期23卷 76-84页

作者： Tao ZHU Xing ZHANG Nengjing YI Haibing LIU Zhenguo LI Institute of Atmospheric Environmental Management and Pollution Control China University of Mining&Technology(Beijing)Beijing 100083People's Republic of China Solid Waste and Chemicals Management Technology Center China Ministry of Ecology and EnvironmentBeijing 100029People's Republic of China National Engineering Laboratory for Mobile source Emission Control Technology China Automotive Technology&Research Center Co.Ltd.Tianjin 300300People's Republic of China State Key Laboratory of Organic Geochemistry Chinese Academy of SciencesGuangzhou 510640People's Republic of China

NOx storage and reduction(NSR)technology has been regarded as one of the most promising strategies for the removal of nitric oxides(NOx)from lean-burn engines,and the potential of the plasma catalysis method for NOx reduction has been confirmed in the past few *** work reports the NSR of nitric oxide(NO)by combining non-thermal plasma(NTP)and Co/Pt/Ba/γ-Al2O3(Co/PBA)catalyst using methane as a *** experimental results reveal that the NOx conversion of NSR assisted by NTP is notably enhanced compared to the catalytic efficiency obtained from NSR in the range of 150°C–350°C,and NOx conversion of the 8%Co/PBA catalyst reaches 96.8%at 350°***(O_(2))has a significant effect on the removal of NOx,and the NOx conversion increases firstly and then decreases when the O_(2)concentration ranges from 2%to 10%.Water vapor reduces the NOx storage capacity of Co/PBA catalysts on account of the competition for adsorption sites on the surface of Co/PBA *** is a negative correlation between sulfur dioxide(SO_(2))and NOx conversion in the NTP system,and the 8%Co/PBA catalyst exhibits higher NOx conversion compared to other catalysts,which shows that Co has a certain SO_(2)resistance.

关键词： non-thermal plasma NOx storage and reduction Co/Pt/Ba/γ-Al2O3 catalyst NOx conversion influence parameter

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Plasticity role in strength behavior of cement-phosphogypsum stabilized soils

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第6期14卷 1977-1988页

作者： Xia Bian Lingling Zeng Feng Ji Ming Xie Zhenshun Hong Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing210098China State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou221116China College of Civil Engineering Zhejiang University of TechnologyHanzhou310014China Jiangsu Water source Company ltd.of the Eastern Route of the South-to-North Water Diversion Project Nanjing210000China Fujian Yongfu Power Engineering Co Fuzhou350108China Institute of Geotechnical Engineering School of TransportationSoutheast UniversityNanjing211189China

Dredged soil and phosphogypsum are frequently regarded as wasted materials,which require further treatment to control their environmental ***,phosphogypsum is proposed as a binder to stabilize dredged soil,aiming at efficiently reducing and reusing these waste *** this study,the engineering properties of cement-phosphogypsum stabilized dredged soils were investigated through a series of unconfined compression tests,and the effects of plasticity index of original soils on the strength improvement were ***,the microstructure test and mineralogical test were performed to understand the mechanism of physical role of original soils in strength *** results revealed that the unconfined compressive strength significantly decreased with the increase in plasticity index at the same binder *** essential factor for strength improvement was found to be the formation of cementitious materials identified as calcium silicate hydrate(CSH),calcium aluminate hydrate(CAH),and ettringite(Aft).The normalized integrated intensity of cementitious materials(CSH+CAH+Aft)by pore volume decreased with the increase in plasticity ***,the density of cementitious materials filling the soil pores controlled the effectiveness of strength *** cementitious materials per pore volume were observed for the original soils with lower values of plasticity *** is,the higher strength of stabilized soils with lower values of plasticity index was attributed to a packed structure forming by integrated fabric through denser cementitious *** can be anticipated from the above findings that the effectiveness of stabilization treatment will significantly reduce with the increase in plasticity of origin soil.

关键词： Strength Stabilization Plasticity index Microstructure Mineralogical analysis

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Research on simulation and application of mine dipole-dipole advance detection device by direct current method

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Meitan Xuebao/Journal of the China Coal Society 2025年第1期50卷 564-571页

作者： Yue, Jianhua Teng, Xiaozhen Xi, Danyang Zhang, Herui Wu, Xiaokang Lu, Kailiang School of Resource and Geosciences China University of Mining and Technology Xuzhou221116 China School of Safety Engineering China University of Mining and Technology Xuzhou221116 China China Coal Group Shanxi Huayu Energy Co. Ltd. Shuozhou036000 China State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep UndergroundEngineering China University of Mining & Technology Xuzhou221116 China

Advanced detection using the direct current (DC) method in underground coal mines is a primary technique for identifying water-bearing structures ahead of the driving face. Traditionally, a three-pole advanced detection device, based on spherical shell theory, has been widely utilized in field applications. However, recent concerns have been raised by scholars regarding the accuracy and resolution of this device. Moreover, the necessity of using infinite electrodes in underground settings results in low construction efficiency and high costs. To address these issues, this paper proposes a dipole-dipole advanced detection device. We assess the device's detection capabilities through a combination of theoretical research, numerical simulations, and analysis of measured data. Initially, we establish a full-space geoelectric model to simulate the electric field distribution characteristics of a DC dipole source, demonstrating the method's reliability and feasibility for advanced DC detection. We then compare and analyze the detection effects and response characteristics to low-resistance anomalous bodies of both pole-dipole and dipole-dipole devices using uniform and varied full-space geoelectric models. Finally, field tests provided valuable insights into the electrical response characteristics at the front of the excavation tunnel. Using the transient electromagnetic advance detection method for comparative analysis, we identified a low-resistance anomaly located between 5 to 45 meters ahead. This anomaly was subsequently confirmed through drilling. The study concludes that the mine's dipole-dipole DC method effectively identifies low-resistance anomalies in front of the driving head. This method not only offers high detection accuracy and construction efficiency but also saves significant manpower and material resources, highlighting its theoretical significance and practical application value. © 2025 China Coal Society. All rights reserved.

关键词： Coal mines

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Report on 3,143.6-km Time and Frequency Transfer Fiber Link with Ps-level Stability

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Chinese Physics Letters 2025年第1期42卷 68-72页

作者： Bo Liu Xinxing Guo Jiang Chen Yanli Zhou Tao Liu Ruifang Dong Shougang Zhang National Time Service Center Chinese Academy of SciencesXi'an 710600China University of Chinese Academy of Sciences Beijing 100039China Key Laboratory of Time Reference and Applications Chinese Academy of SciencesXi'an 710600China China Mobile Communications Group Shaanxi Co. LtdXi'an 710600China

This letter describes the implementation of a high-precision time and frequency transmission system using a two-way and wavelength division multiplexing scheme over 3,143.6 km of field fiber links,connecting 21 sites between Xi’an and Beijing,*** scheme incorporates a link noise clean-up system(LNCUS),wherein a controlled very-low-phase noise BVA oscillator acts as an internal frequency source at the relay site to effectively suppress the interference caused by the fiber link ***,the high-stability pulse generation technology in the LNCPS provides sufficient short-term stability to significantly improve the stability of the fiber time *** results indicate a time transfer stability in terms of time deviation(TDEV)of less than2.07 ps@1s,5.9 ps@100,000s,and combined uncertainty of less than 49.29 ps for the 3,143.6 km field fiber *** results represent a significant breakthrough in achieving high-accuracy time transfer and continuous operation over ultralong-span field optical fibers exceeding 3,000 km for the first *** enabled time transfer and synchronization services over the longest international optical fiber distance,thereby establishing a fundamental basis for constructing a nationwide high-precision time service through optical fiber networks.

关键词： fiber breakthrough exceeding

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